President Trump is angry the U.S. Navy isn’t using more steam power. He sent the Navy scrambling Thursday after he suggested it scrap an already-built electro-magnetic catapult system on its brand-new aircraft carrier and replace it with a “goddamn steam” one.

In excerpts from an interview with Time magazine published Thursday, Trump slammed the catapult launch system on the USS Gerald Ford, the new, high-tech supercarrier slated to become the crown jewel of the U.S. Navy. The new system, the Electro-Magnetic Aircraft Launch System (EMALS), replaces the old steam-powered catapult launch system for hurling jets off a short runway, albeit with heftier up-front costs. Which really peeved the commander-in-chief.

Trump, per the Time interview:

I said, “You don’t use steam anymore for catapult?” “No sir.” I said, “Ah, how is it working?” “Sir, not good. Not good. Doesn’t have the power. You know the steam is just brutal. You see that sucker going and steam’s going all over the place, there’s planes thrown in the air.” It sounded bad to me. Digital. They have digital. What is digital? And it’s very complicated, you have to be Albert Einstein to figure it out. And I said – and now they want to buy more aircraft carriers. I said, “What system are you going to be-” “Sir, we’re staying with digital.” I said, “No you’re not. You going to goddamned steam, the digital costs hundreds of millions of dollars more money and it’s no good.”

A sled moves along the flight deck of the USS Gerald R. Ford on Feb. 16, 2016, during a test of the catapults that comprise part of the ship’s Electromagnetic Aircraft Launch System, or EMALS. Navy photo by Mass Communication Specialist 3rd Class Kristopher Ruiz

The Navy didn’t immediately respond to a request for comment or reaction, but is expected to address the commander in chief’s remarks in a statement.

Many defense experts who aren’t Albert Einstein are rebuffing Trump’s claims, though.

For starters, there’s one big problem: Trump’s criticism is a few years too late. The Ford is already built after almost a decade in the shipyard, EMALS system and all. Experts say it’s virtually impossible to sort out how to replace the existing EMALS system with the old steam-powered system, and that could cost billions of dollars.

Plus the Ford has the EMALS system for a reason: It confers a whole bevy of advantages over its steam-powered predecessor, said Andrew Holland of the American Security Project. It has fewer points of failure, it’s lighter, and it’s more energy efficient with up to 30 percent more energy behind each launch – perfect for heavy fighters. And unlike the steam-powered catapult, the Navy can calibrate each launch’s speed to whatever type of plane (or drone) is taking off of its deck.

Catapults are part of what makes U.S. carriers a bigger, better breed of warship than those of other countries. China’s new flat top, and Russia’s old one, don’t even have steam catapults, but rather a sloped, ski-lift deck. That limits the kind of aircraft and payloads they can carry.